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ENTM 010
Dr.Erin Wilson Rankin

Week 1, Lecture 2, 4/2/2014 Taxonomy: Science of identifying and classifying different organisms based on similar characteristics -simply classifying species Typically use Linneaus systeana, -Grouping species based on similiar characteristics which means it hierarchical -Binomial nomenclature, Genus and Species -Genus is always capitalized whereas the species name is not capitalized, both always italicized Relations among taxa -Monophyly: derived (=evolved) from a single common ancestor -a monophylectic group: only and all closely related species -a monophylectic trait is a trait that would be shared among all species such as wings in insects -Polyphyly: derived from multiple common ancestors -these traits would characterize organisms Annelida: "ringed worms" -bilaterally symmetrical -segmented -gas exchange via skin -bristles on segments -closed circ. system -Australia has some snake sized earthworms, glimpse of the past Onychophora: "walking worms" -link between annelids and arthropods -bilaterally symmetrical -have antennae, used for sensing -have legs or stubby feet -breathe through trachea, have airholes to take in air to breathe -open circulatory system -have an exoskeleton Arthropoda: "jointed foot" -Bilaterally symmetrical -exoskeleton -open circ system -trachea(terrestrial) or gills(aquatic/marine) -multiple body segments -jointed appendages Subphylum Trilobites (extinct) -crustaceans evolved from this? Subphylum Chelicerata -spiders, scorpions, mites, ticks, horseshoe crabs etc -means clawed horns "chelicerae" -pedipalps, behind the mouth, usually associated with sensation -do not have antennae -4 pairs of legs and simple eyes Arachnids, Largest group within Chelicerae -scorpions light up in the dark, due to fluorescent chemicals inside scorpions -many are toxic, but very few have venom harmful to humans, e.g. mouse spiders, venomous but only painful -black widow spider bites, highly venomous and only deadly if not treated with anti- venom -Brown Recluse Spider, most deadly spider in North America, deadly if provoked -Brazilians Wandering Spider "Most Venomous" -Daddy Long Legs, aren't spiders, they are Opiliones, a seperate arachnid order from spiders that have no venom glands -6 fatalies in spider bites a year, most of which are due to allergic reactions -arachnids includes mites and ticks -Ticks have a harder leathery exoskeleton while mites have a thinner one -ticks are always parasitic, must survive on a host, mites can survive without a host Sub-phylum Crustacea: -Lobster, crab, shrimp, barnacles, isopods (pillbug) -two pairs of antennae -mostly aquatic -found in moist soil habitats -at least five pairs of legs -two main body segments, seppelo thorax (head+muscles) and abdomen -most have gills -bilateral symmetry -all appendages are paired Sub-phylum Myriapoda -Millipedes and centipedes -one pair of antennae, dont have any type of joint -bilateral symmetry -many legs and all appendages are in pairs ->Millipedes, elongated in shape and pretty round -two pairs of legs per body segment ->centipede is not tubular -one pair of legs per segment -first pair of appendages are modified legs that inject poison -never have an even # pair of legs Sub-Phylum Hexapoda -Protura, diplura, collembola, insecta -these three groups have internal mouth parts -protura are more of cone headed organisms -Diplura: two pronged pristle tails -all three can be found in soil -Collembola: "spring tails" can jump 50-100 times their body length Class Insecta -3 body segments 1. head 2. thorax, attachment of all the appendages, thorax are divided into three sections, wings are lower section, all legs are attached, full of muscle 3. Abdomen: digestion and internal food storage -Mostly terrestrial -associated with seed plants Week 1 4/4/14 Lecture 3 -More insect species than any other species, evolutionary success Why So many, Splitting into different species 1. different species cannnot interbreed 2. different species have different evolutionary paths -Natural selection: process whereby organisms better adapted to their environment tend to survive and produce more offspring -Artificial selection: selective breeding, process whereby organisms are preferentially bred because of desired traits farmers have been participating in this since beginning of agriculture, for example many plants developed out of wild mustard plants such as caulfilower -by selecting different traits you can alter the phenotype Natural Selection 1.Individuals of species do not reproduce equally 2. Most populations are stable in size, you can only go up to a certain point before other factors such as resources start to limit it 3.Resources are limited, can cause agression amongst species Resource Limitation: environment can support limited numbers of organisms Niche: describes the way of life of a species -its special place in its environment -how a species respsonds to a distribution of resources and how they alter them as well -Individuals are different despite we are the same species 4. Individuals differ- they exhibit phenotypic variation -Genetic differences cause phenotypic variations, subtle changes can lead to big phenotypic differences -Random mutation causes variation. DNA, can be beneficial/maleficient -Environment can modify phenotype too, but cannot be inherited -Disease, nutrition Evolution by Natural Selection -Phenotypes that provide fitness advantage will be positively selected Variation: Differential Reproduction: certain species arent as successful as reproducing compared to others Examples of Natural Selection -For example drought hit Galápagos Islands, beak size increased 10% due to availability of bigger nuts/seeds due to weather -Insecticide resistance, random mutations in certain mosquitoes granted resistance to insecticides which spread through insect population Why are Insects so successful? 1. Tough & protective exoskeleton, prevents water loss due to high surface area, protects them from temperature extremes, 2. Serves as armor to protect them from predators, pathogens, and the environment as well. 3. provides frame for flight, e.g. muscles and it provides rigidity 1. Small Size -avoid predators due to maneuverability -requires fewer resources, they consume less -niche availability, more places to go, for example an ant can go to much more places than a lion can 2. High Reproductive rate -high fecundity, e.g. 1 mosquitoe can have hundreds of babies in a week -Short development time, partially due to small size, for example an aphid can go through a generation in five days. most species that are not social have no care, which is why they lay many eggs at once 3. Parthogenesis: asexual reproduction in which growth and development of embryos occur without fertilization Bees: unfertilized eggs can develop into male bees Aphids: clonal reproduction -> females can produce exact same version of herself 4. frequent reproduction and short development time means insects are high adaptable Complete Metamorphosis -do not look anything like they were originally Wings and Ability to Fly -Insects are few of the animals that can fly -gives a lot of flexibility Sociality: some bees, some wasps, all ants and termites -Social as in living together in a related group, few reproductive females 1. Cooperation, Brood Care -All the queen does is lay eggs so workers have to take care of everything -Nest Maintenance: cleaning out the nest 2. Overlapping generations -multiple generations active in the nest in the same time 3. Division of labor Week 2 Lecture 4: External Anatomy -Related Arthropods, insects are diverse, insects have evolved to adapt to many to environment Starting from the Outside... The Exoskeleton -Setae: hair, some setae have evolved into scales -Epicuticle: thin layer that serves to protect the insect as well as water loss -Exoskeleton: structural support and strength as well as to reduce water less -The exoskeleton is molted as insects grow in size Insect Tagmata (three tagma): "classic" insect 1. Head: eating and sensing, six segments, five pairs of appendages modified for food usage 2. Thorax: wings 3. Abdomen: Digestion and reproduction "Modified" Insect Forms "Classic" Mouth Mandible: Crush food Maxilla: manipulate food as well as sensing food Labium: Eyes: major sensory structure, takes much of an insects face Compound Eye: Ommatidia: light sensing units of the eyes, these compound eyes form mosaic images -sense movement and light extremely fast Eyes: Ocelli -both adult and mature insects have this Eyes:stemmata -immature insects have this, senses light differences which helps guide its direction, "classic" antennae -Aristate: johnson organs -Filiform -Flabellate: -Clubbed pAntennae: mostly used for chemoreception -insects use pheromones to understand the environment -Pheromones: sex pheromones Mechanoreception: sensing sounds Johnston's organs: located in the pedicel of the antennae, detects vibration (air movement) impacting the flagellum and helps flying manage flight -Tymphanal Organ: a membrane stretched like a drum head Mouth eating, antennae/eyes: sensing Thorax Pleuron: "Classic" Wing -generally insects have two sets of wings "Modified" Wings -opened up many niches and opportunities Tegmina: Grasshoppers Elytra: hardened forewings, ladybugs, provides protection Hemelytra: half wing, partly leathery and partly hardened, true bug family, stinkbugs "Classic" Leg Coxa: similiar to a hip attached to the main body of the insect Trochanter: attached to the femur, allows for flexing between the legs Tibia: Tarsus: attached to the claws Cursorial Legs: known for running Raptorial Legs: grabbing Prolegs: Basic functions of the Thorax are for locomotion, wings and legs Tagma: The abdomen Spiracles: Modified Abdomen: Cerci: some insects have this, end of abdomen, helps with sensing as well as reproductive Reproduction :ovipositorStinger is a mdified ovipositor, regular bees have barbed stinger which dies because the barb gets detached Reproduction: Aedags Entomology Lecture 4 April 8 Internal Anatomy -Gas Exchange -Circulation of "blood" -Fat body -Digestive system -excretory system Being so small has its issues -Higher surface to mass ratio, smaller organisms have more surface area relative to their mass -can absorb fall damage better, susceptible to water loss due to small size, can result in desiccation(drying out)death Passive diffusion: open system Active ventilation: oxygen directly touches muscles Gas Exchange: closed tracheal system these organisms live aquaticly insects dont need blood as much as we do because insects do not have veins and arteries as we do, hemolyphs can just circulate throughout the body Circulation of hemolyph, can be 20-30% percent of insect body weight Fat Body Digestive System -Pharynx helps with suction -food passes through the esophagus -Crop: place for temporary storage in insects -Malphigian tubules: maintain homeostasis, similiar to kidneys -Ammonia builds up , converted to uric acid due toxicity Nervous System -Ganglia bundled up = neurons -Each ganglia controls separate segments, therefore controlling different body segments -Insects with mushroom bodies have better capacity to learn from previous experience Reproduction: bisexual reproduction Nuptial Gift Parthenogenetic reproduction -aphids can reproduce asexually Halpdiploidy: Viviparous: give live birth, eggs remain in body and get nourished within Oviparous: give birth to eggs Ovoviviparous 4/11/14 Notes So when you get too big from your skin, shed it and get another, sometimes you even lose your head, this is called molting Regulation of molting: hormonal Control Sensory Input: exeskeleton too small Neurons secrete brain hormone: triggers a cascade stimulating the prothoracic gland Ecdysone Concentration, when this decreases you have the molting process Metamorphosis: change from immature to adult involves multiple changes in form during development Multiple stages (not all types have these types of stages) egg, nymph etc Development Terminology Instar Larval stages during the developmental process Stadium: time between instars, different molts Diapause: period of arrested development, often in the pupal stage Voltinism:How many generations e-this is looking at how many broods/generations are produced per year Univoltine: this particular is one generation Bivoltine: two generations such as the speckled moth Multivotine: Metamorphosis Types Ametabolous Insects: look similiar to hatched, adults look similiar to the nymphs, basically an enlarged version such as the silverfish, adults do not have wings Hemimetabolous: simple metamorphosis, incomplete metamorposis, wing pads are present in juveniles, wings in adults. Adults look like nympts except for wings Holometabolous: complete metamorphosis: adults look very different from larvae Larva: juvenile form, no wings, no compound eyes Adult: dispersal Metamorphosis: Niches across Development -Ametabolous: all life stages in same habitat -Heminemetabolous: all life stages tend to be in similiar environments and eat similiar foods -Holometabolous: Larvae are frequently in very different habitats Exceptions modified form of hemimetabolism 1) white fly 2) male scales First nymphal stages are mobile, intermediate stages are sessile, pupate within the final nymphal skin, Sensory Function 1) taste and smell (chemoreception) 2) touch, pressure, vibration (mechanoreception) 3) sound (auditory) 4) vision Chemoreception Taste: detecting concentrations often fluid, receptors are often found on mouthparts or in foregut, there are exceptions as well. swallowtail butterflies have taste receptors on their feet Smell: detecting concentrations: air, fluid, surface. Receptors most often on or near antennae Taste AND smell: hairs, pegs, plates, pits. Functions: determine if appropriate host, sexual signaling,trail marking, alarm or defense communication Mechanoreception sFunctions of mechanorecepto 1. detect movement 2. Detect gravity which is way down 3. Detect vibration Auditory Reception Functions of auditory receptors 1. Locate Mates 2. detect enemies Vision Insect simple eyes: ocelli Insect compound eyes generate a mosaic world view and likely have some distortions based on domed cornea Flicker fusion frequency: allows them to see discrete shapes and respond to movement 4/14/14 Metamorphosis: know all three types and stage What can honeybees see that we cannot? Flicker Fusion Frequency: How fast you can see and process visual stimulus, the higher this is, the more visual information is going to your brain. And it means that you can respond to visual input much more quickly. Function: by having a flicker fusion threshold, insects can respond to things more quickly Hormonal control of molts and metamorphosis Hormone vs Pheromone, what is the difference? -Ecdysone regults molting u-Juvenile Hormones regulate metamorphosis Voltinism: -often under genetic control-evolved in response to the environment Recall: Natural Selection:Phenotypes that a the most beneficial will ave higher fitness and pr
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